U.S. patent number 6,122,169 [Application Number 09/422,136] was granted by the patent office on 2000-09-19 for heat sink assembly.
This patent grant is currently assigned to Foxconn Precision Components Co., Ltd.. Invention is credited to Pao Lung Lin, Eric Liu, Chun-Hsin Lu.
United States Patent |
6,122,169 |
Liu , et al. |
September 19, 2000 |
Heat sink assembly
Abstract
A heat sink assembly of the present invention comprises a
conductive housing with a heat pipe and a fan fixed therein, and
fixing devices. The conductive housing is formed by die-casting and
comprises a base, a heat sink portion and a shielding portion which
depend downwardly from the square base. The base defines a thorough
channel to fix the heat pipe for dissipating heat produced by an
electronic element mounted in the shielding portion, two legs of
the channel being communication with the space formed by the
shielding portion and the heat sink portion respectively. The
shielding portion is integral with the heat sink portion and
defines a peripheral side wall to form a sealed square-shaped space
together with the base to provide EMI shielding for the electronic
element. A hole is defined in each of the four corners of the
peripheral side wall of the shielding portion to engage with the
fixing devices.
Inventors: |
Liu; Eric (Tu-Chen,
TW), Lin; Pao Lung (Taipei, TW), Lu;
Chun-Hsin (Taipei, TW) |
Assignee: |
Foxconn Precision Components Co.,
Ltd. (Taipei Hsien, TW)
|
Family
ID: |
21641608 |
Appl.
No.: |
09/422,136 |
Filed: |
October 20, 1999 |
Foreign Application Priority Data
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|
|
|
|
Jul 22, 1999 [TW] |
|
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88112484 |
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Current U.S.
Class: |
361/700;
165/104.33; 165/121; 257/723; 257/E23.099; 361/679.47; 361/679.54;
361/695; 361/702; 361/710; 361/802; 361/816; 454/184 |
Current CPC
Class: |
H01L
23/467 (20130101); H01L 2924/0002 (20130101); H01L
2924/0002 (20130101); H01L 2924/00 (20130101) |
Current International
Class: |
H01L
23/34 (20060101); H01L 23/467 (20060101); H05K
007/20 () |
Field of
Search: |
;361/683,687,690-695,697,699,700-705,707,709,710,720-723,727,802,803,816,818
;257/706-727 ;174/15.1,16.3,252 ;454/184
;415/115,177,178,208.3,213.1,214.1
;165/80.2,80.3,80.4,121,122,106,106.33,104,104.32,104.33,185 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Picard; Leo P.
Assistant Examiner: Datskovsky; Michael
Attorney, Agent or Firm: Chung; Wei Te
Claims
What is claimed is:
1. A heat sink assembly for protecting an electronic element
mounted on a printed circuit board, comprising:
a conductive housing including:
a base defining a channel consisted of a first part and a second
part,
a heat sink portion integrally depending downward from the base,
the heat sink portion being in contact with one of the first and
the second parts of the channel, and
a shielding portion being integral with the heat sink portion and
depending downward from the base, the shielding portion together
with the base defining a space for surrounding an electronic
element to providing EMI shielding to the electronic element, the
space being in communication with the other of the first and the
second parts of the channel;
a group of fixing devices for fixing the conductive housing to a
printed circuit board;
a heat pipe being fixed in the thorough channel of the base for
dissipating heat produced by the electronic element; and
a fan being fitted in the heat sink portion of the conductive
housing to generate air circulation between the heat sink portion
and outside for aiding in cooling the heat sink portion.
2. The heat sink assembly as claimed in claim 1, wherein the base
is substantially rectangular shaped.
3. The heat sink assembly as claimed in claim 1, wherein the heat
sink portion and the shielding portion of the conductive housing
are integrally formed with the base.
4. The heat sink assembly as claimed in claim 1, wherein the heat
sink portion defines a peripheral side wall, an outlet and an
inlet.
5. The heat sink assembly as claimed in claim 4, wherein the
periphery side wall of the heat sink portion defines an arc-shaped
space and a plurality of fins extends from one portion of the
arc-shaped space, the fins depending from the base and having a
uniform height substantially equal to that of the peripheral side
wall.
6. The heat sink assembly as claimed in claim 5, wherein the other
portion of the arc-shaped space of the heat sink portion forms a
plurality of projections arranged in a rotary configuration to
engage with the fan, each of projections being in an arc shape and
depending downward from the base.
7. The heat sink assembly as claimed in claim 1, wherein the space
of the shielding portion is enclosed by a closed periphery side
wall.
8. The heat sink assembly as claimed in claim 7, wherein the closed
periphery side wall of the shielding portion is substantially in a
square shape.
9. The heat sink assembly as claimed in claim 8, wherein the
shielding portion defines a respective hole adjacent to each of
four corners of the peripheral side wall thereof.
10. The heat sink assembly as claimed in claim 9, wherein each of
the holes of the shielding portion extends through the shielding
portion into the base and defines an upper portion and a lower
portion smaller than the upper portion in diameter, a lip being
formed at a junction of the upper portion and the lower
portion.
11. The heat sink assembly as claimed in claim 1, wherein each
fixing device comprises a bolt, a spring and a nut enclosing and
being fitted with the bolt respectively, and is fixed in respective
hole of the shielding portion.
12. The heat sink assembly as claimed in claim 11, wherein the bolt
of the fixing device comprises an end cap, a shank and a screw
portion.
13. The heat sink assembly as claimed in claim 12, wherein the
diameter of the end cap of the bolt is slightly smaller than that
of the upper portion of the hole in the shielding portion.
14. The heat sink assembly as claimed in claim 12, wherein the
diameter of the shank of the bolt is smaller than that of the end
cap and substantially equal to that of the lower portion of the
hole of the shielding portion.
15. The heat sink assembly as claimed in claim 12, wherein the
spring of the fixing device encloses a periphery of the shank and
bears against the end cap of the bolt at an upper free end thereof
and the lip of the hole at a lower free end thereof,
respectively.
16. The heat sink assembly as claimed in claim 12, wherein the
diameter of the screw portion of the bolt is smaller than that of
the shank and the screw portion of the bolt has screw threads
fitted with the nut of the fixing device.
17. The heat sink assembly as claimed in claim 1, wherein the heat
pipe and the channel in the base of the conductive housing are both
L-shaped.
18. The heat sink assembly as claimed in claim 1, wherein the fan
comprises a fan housing and defines four fixing holes in four
corners for respectively aligning with four screw holes defined
near the projections in the heat sink portion.
19. An assembly for use within a computer, comprising:
a printed circuit board with an electronic element mounted
thereon;
a heat sink assembly secured to said printed circuit board, said
heat sink assembly including a base with a heat sink portion and a
shielding portion thereon;
said shielding portion including a downward extending peripheral
wall defining a circumferentially sealed first space therein
between the base and the printed circuit board wherein said
electronic element is embedded in said first space;
said heat sink portion defining a second space with an inlet and an
outlet thereabout to communicate with an exterior, a plurality of
fins formed in the second space adjacent to the outlet, a fan
disposed in the second space adjacent to the second inlet; and
a heat pipe attached to the base, of which one end extends around
the first space to absorb heat generated by the electronic element,
and the other end extends around the second space to dissipate said
heat through said fins.
20. A heat sink assembly comprising:
a plate-like base;
a heat sink portion integrally downward from the base and defining
therein a ventilation space with an inlet and an outlet in opposite
ends;
an array of fins formed in the ventilation space adjacent to the
outlet;
a fan disposed in the ventilation space adjacent to the inlet;
a shielding portion integrally downward from the base and defining
a circumferentially sealed space; and
a heat pipe thermally connected between said ventilation space and
said sealed space.
Description
BACKGROUND OF THE INVENTION
The present invention relates to a heat sink assembly, and
particularly to a heat sink assembly which can provide EMI
shielding for protected electronic elements while providing
effective heat dissipation.
Computer technology today transmits information at higher and
higher rates. As transmission speed increases, the heat produced by
the internal electronic elements increases correspondingly. This
heat must be dissipated efficiently, otherwise the rising
temperature in the computer will cause a system malfunction.
Referring to U.S. Pat. No. 4,884,331, a prior art heat sink
assembly comprises a heat sink having a conductive base. A
plurality of fins are formed on a top surface of the base and an
electronic element is located under the base and abutted against a
bottom surface thereof, whereby heat produced by the electronic
element is dissipated through the fins on the base. However, using
this means, the assembly is fairly high profile, which does not
accord with the low profile development trend in computers, and
minimal EMI protection is provided. Additionally, one means
commonly used to fix such a heat sink assembly to the chip is
similar to the structure shown in U.S. Pat. No. 5,621,615. This
means provides an uneven retaining force, and therefore the
electronic element may not make effective contact with the heat
sink, and heat dissipation may be adversely affected.
Another heat sink assembly is shown in FIG. 4. This heat sink
assembly comprises a rectangular shaped base 11, a first heat sink
13 mounted on the base 11, a second heat sink 15 also mounted on
the base 11 some distance away from the first heat sink 13 and a
heat pipe 17 running beneath the two heat sinks. The heat sink
assembly is mounted with the second heat sink 15 directly above the
electronic element which is to be cooled. Channels 12 and 16 are
defined in the middle positions of the first and the second heat
sinks 13, 15 to install the heat pipe 17. A fan 19 is mounted on
the first heat sink 13 to improve the effectiveness of the heat
sink. Although this heat sink assembly is low profile, product
assembly is fairly involved.
In addition, the increasing frequency of the signals used in
computers is causing increasingly severe EMI shielding problems,
which need to be taken into account. However, the aforementioned
heat sink assemblies do not provide effective EMI shielding for the
electronic elements.
Therefore, a heat sink assembly which can provide EMI shielding for
the protected electronic elements is needed.
BRIEF SUMMARY OF THE INVENTION
A first object of the present invention is to provide a heat sink
assembly which can provide EMI shielding for protected electronic
elements;
A second object of the present invention is to provide a heat sink
assembly which is easily manufactured and has a good heat sink
effectiveness.
A third object of the present invention is to provide a heat sink
assembly which is retained on the printed circuit board using an
even retaining force.
A heat sink assembly of the present invention comprises a
conductive housing, a heat pipe and a fan fixed therein, and fixing
devices. The conductive housing is integrally formed by die-casting
and comprises a rectangular-shaped base, a heat sink portion and a
shielding portion which depend downwardly from the base. The
shielding portion is integral with the heat sink portion and has a
peripheral side wall to form a sealed square-shaped space together
with the base for providing EMI shielding for electronic elements
mounted therein. A hole is defined in each of four corners of the
peripheral side wall of the shielding portion to engage with the
fixing devices. The heat pipe is fixed in a channel defined in the
base to dissipate heat produced by the electronic elements. The fan
is
fitted in the heat sink portion to aid in the air circulation
between the heat sink portion and outside for cooling the heat sink
portion.
Other objects, advantages and novel features of the invention will
become more apparent from the following detailed description of the
present embodiment when taken in conjunction with the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an exploded view of a heat sink assembly of the present
invention;
FIG. 2 is a perspective view from another viewpoint of a conductive
housing of the present invention;
FIG. 3 is a partial sectional view taken at line 3--3 in FIG.
1;
FIG. 4 is a perspective view of a prior art heat sink assembly.
DETAILED DESCRIPTION OF THE INVENTION
Although a heat sink assembly of the present invention may be used
with such electronic elements as a CPU, an accelerated graphics
chip (AGC) and other components, only a CPU is used as an example
in this description of a preferred embodiment.
FIGS. 1, 2 show a heat sink assembly 30 of the present invention
for being mounted to a printed circuit board 20 to protect a CPU 22
mounted on the printed circuit board 20. The heat sink assembly 30
of the present invention comprises a conductive housing 32, a heat
pipe 36 and a fan 26 mounted therein, and fixing devices (not
labeled). The conductive housing 32 is integrally formed by
die-casting and comprises a rectangular-shaped base 34, a heat sink
portion 40 and a shielding portion 54 which depend downward from
the base 34. The heat sink portion 40 defines an arch-shaped space
44 enclosed by a peripheral wall 42. The peripheral side wall 42
has an open end 421 at one end thereof and a cutout 52 defined in
the other end thereof opposite to the open end 421. The cutout 52
functions as an inlet for the fan 26. An end portion of the space
44 defines a plurality of fins 46 depending downward from the base
34 adjacent to the open end 421 of the peripheral wall 42. The
plurality of fins 46 are arranged in an array and have a uniform
height which is substantially equal to that of the peripheral wall
42. The other portion of the space 44 forms a plurality of
arc-shaped projections 48 arranged in a rotary configuration to
guide the flow of air driven by the fan 26 fixed within the space
44. Four screw holes 49 are defined near the projections 48 and
align with four corresponding fixing holes 29 defined in a fan
housing (not labeled) of the fan 26 for screws (not shown)
extending therethrough to fix the fan 26 in the space 44 of the
heat sink portion 40.
The shielding portion 54 of the conductive housing 32 is integral
with the heat sink portion 40, its peripheral side wall defining a
sealed square-shaped space with the base 34 to provide EMI
shielding for the CPU 22 located therewithin. Additionally, the
base 34 defines a thorough channel 38 in the shape of the letter
"L", two legs of the channel 38 being communication with the
shielding portion 54 and the plurality of fins 46 of the heat sink
portion 40 respectively. The heat pipe 36 is correspondingly formed
in the shape of the letter "L" and is filled with a conductive
fluid for dissipating heat from the CPU 22.
Referring to FIGS. 2, 3, a hole 56 is defined in each of the four
corners of the peripheral side wall of the shielding portion 54 for
a group of fixing devices to fit in. The holes 56 extend through
the base 34 into the corners of the peripheral side walls of the
shielding portion 54, and define an upper portion 57 and a lower
portion 58. The lower portion 58 thereof is proximate the printed
circuit board 20 when the heat sink assembly 30 is mounted to the
printed circuit board 20. A lip 581 is formed at the junction of
the lower portion 58 and the upper portion 57, the lower portion 58
being of a smaller diameter than the upper portion 57. The group of
fixing devices each comprise a bolt 60, a spring 68 and a nut 66.
The bolt 60 comprises an end cap 62, a shank 61 and a screw portion
64 in sequence. The end cap 62 defines a recess 65 in a middle
portion of a top surface for a screwdriver (not shown) to insert.
The diameter of the end cap 62 is slightly smaller than that of the
upper portion 57 of the hole 56 to be fully received therein, so as
not to be outwardly exposed. The diameter of the shank 61 of the
bolt 60 is smaller than that of the end cap 62 and is substantially
equal to that of the lower portion 58 of the hole 56. The spring 68
encircles a periphery of the shank 61, two ends of the spring 68
abutting the end cap 62 at an upper end and the lip 581 at a lower
end. The screw portion 64 of the bolt 60 extends through a bolt
hole 24 defined in the printed circuit board 20 and engages with
the nut 66, thereby fixing the heat sink assembly 30 to the printed
circuit board 20.
In assembly (referring to FIG. 1), the heat pipe 36 is fixed in the
channel 38 of the conductive housing 32 with a conductive adhesive.
The fan 26 is fixed with the projections 48 in the space 44 of the
heat sink portion 40 with the screws extending through the fixing
holes 29 thereof into the screw holes 49 defined in the base 34.
The conductive housing 32 combination assembly is then placed on
the printed circuit board 20 so that the holes 56 in the housing 32
align with the bolt holes 24 in the printed circuit board 20, so
that the shielding portion 54 of the housing 32 encloses the space
around the CPU 22, thereby providing EMI shielding. The bolts 60
are inserted through the springs 68 and each of these is inserted
into each of the corresponding holes 56 in the conductive housing
32 and then through the bolt hole 24 in the printed circuit board
20, the nut 66 then being engaged and tightened to the bolt 60.
Because the heat sink assembly 30 of the present invention fully
encloses the CPU 22, it provides an effective EMI shield. Because
the conductive housing 32 of the heat sink assembly 30 is
integrally die-cast, the manufacture and assembly of the heat sink
assembly 30 are fairly easy. Moreover, the spring 68 of the fixing
device provides an even retaining force between the bolt 60 and the
heat sink assembly 30, thereby improving the method of fixing over
the prior art.
It is to be understood, however, that even though numerous
characteristics and advantages of the present invention have been
set forth in the foregoing description, together with details of
the structure and function of the invention, the disclosure is
illustrative only, and changes may be made in detail, especially in
matters of shape, size, and arrangement of parts within the
principles of the invention to the full extent indicated by the
broad general meaning of the terms in which the appended claims are
expressed.
* * * * *